1. Field of the Invention
The present invention relates to an apparatus for measuring characteristics of optical fibers by employing a plurality of light sources.
2. Description of the Prior Art
In the optical fiber measuring apparatus of this type, inputting/outputting of light beams emitted by laser diodes constituting the light sources as well as echo light beams from an optical fiber due to the back scattering or the like phenomena in correspondence to the laser light beams must be processed by a single optical connector. Consequently, various types of optical switches and optical couplers/decouplers are required.
As the optical switch, there is universally employed an acoustooptical device (hereinafter referred to as A/O modulator) in view of insignificant polarization characteristics and the capability of high-degree isolation between the signals to be processed.
At present, for the measurement of the optical fibers, there are made use of two wavelengths of 1.3 .mu.m and 1.55 .mu.m as light sources. To this end, there must be provided two light sources of the different wavelengths mentioned above and light-beam change-over switches.
Further, for the measurement of the characteristics of optical fibers, the measuring instrument or apparatus has to be frequently transported. Accordingly, there exits a need for the apparatus of small size and light weight. When these various components or devices can be housed within a single casing so as to be controlled through operation of switches installed on a control panel of the casing, the measurement can be carried out effectively.